Method for improving the photographic characteristics of vesicular photographic materials

ABSTRACT

Improvement of photographic characteristics of vesicular film such as an increase in its speed and a reduction in its gamma by contact of film prior to exposure with an alkanol having up to about three carbon atoms. Equivalent results are obtained by contact with acetonitrile where the film&#39;&#39;s vehicle is a thermoplastic linear poly (hydroxy ether) polymer of an epihalohydrin and a dihydric phenol. In both cases where such treatment is followed by a second treatment with water an even greater improvement in photographic characteristics is obtained. Following treatment an equilibration period is required to permit solvent to be released from the film.

United States Patent 11 1 Nishino [75] Inventor: Akio Nishino, Los Gatos, Calif.

[73] Assignees Xidex Corporation, Sunnyvale,

Calif.

22 Filed: Mar. 29, 1973 21 Appl. No.: 346,202

Related US. Application Data [63] Continuation-in-part of Ser. No. 124,584, March 15,

1971, abandoned.

52 Us. or. 96/27 R, 96/48 111), 96/4975, 96/91 R, 96/115 R 51 int. c1.. G03C 5/04, 0036 5/18 [58] Field Of Search... 96/4975, 91 R, 91 N, 11 SR, 96/48 no, 27 R [56] References Cited UNITED STATES PATENTS 2,911,299 11/1959 Baril et a1. 96/49 3,032,414 5/1962 James et a1. 96/49 3,108,872 10/1963 McMahon 96/49 3,120,437 2/1964 Lindquist 96/49 3,143,418 8/1964 Priest et a1 96/49 3,149,971 9/1964 Baril ct al. 1 96/49 3,498,786 3/1970 Notley er a1 96/49 3,615,476 10/1971 Cossicrs ct al 96/49 3,615,486 10/1971 Dclzenne 96/49 FORElGN PATENTS OR APPLICATIONS 645,825 11/1950 Great Britain 96/91 R Primary ExaminerCharles L. Bowers, Jr. Attorney, Agent, or Firm-Townsend and Townsend 5 7] ABSTRACT Improvement of photographic characteristics of vesicular film such as an increase in its speed and a reduction in its gamma by contact of filmprior to exposure with an alkanol having up to about three carbon atoms. Equivalent results are obtained by contact with acetonitrile where the films vehicle is a thermoplastic linear poly (hydroxy ether) polymer of an epihalohydrin and a dihydric phenol. 1n both cases where such treatment is followed by a second treatment with water an even greater improvement in photographic characteristics is obtained. Following treatment an equilibration period is required to permit solvent to be released from the film.

13 Claims, No Drawings METHOD FOR IMPROVING THE PHOTOGRAPHIC CHARACTERISTICS OF VESICULAR PHOTOGRAPHIC MATERIALS.

This is a continuation-in-part of copending U.S. Pat. application Ser. No. 124,584, filed Mar. 15, l97l now abandoned.

This invention relates to vesicular film. More particularly it relates to the treatment of vesicular film to improve its photographic characteristics such as speed and gamma.

Previously it has been disclosed that the treatment of vesicular film with an aqueous bath in liquid or vapor phase at elevated temperatures prior to exposure and development will reduce the gamma or contrast of the film providing a longer grey scale without sacrificing other desirable photometric characteristics. While reducing the gamma the treatment also provides an increase in the photographic speed of the film; see for example, U.S. Pat. No. 3,149,971 to Baril, Jr., et al. issued Sept. 22, 1964.

The present invention is based upon the discovery that these improvements and others are not solely obtainable by treatment of the film with water. It has now been discovered that certain organic solvents in liquid or vapor phase provide similar benefits to vesicular film. Use of these newly discovered organic fluids have certain advantages over the previously disclosed water treatment. For example, in the present method treatment of vesicular film can be executed at ambient temperature whereas the prior. art has required the use of elevated temperatures. Moreover, in the preferred embodiment of the present invention, and as will be illustrated hereinafter, the treatment is more effective and faster than the prior art methods.

ln accordance with the present invention the photographic characteristics of vesicular film are improved by contacting the film prior to exposure with a-fluid phase alkanol having up to about 3 carbon atoms for a time and at a temperature sufficient to increase the photosensitivity thereof.

ln another aspect of the invention in which the vesicular film has as its vehicle a film forming thermoplastic linear poly (hydroxy ether) polymer of an epihalohydrin and a dihydric phenol, the photographic characteristics can be improved-by contacting the film prior to exposure with fluid phase acetonitrile. In both aspects of the invention significant and substantial improvements are obtained by treatment with the organic fluids noted. However, where an even greater improvement is desired, a second treatment by contacting the film with water following the initial contact with the organic fluid will result in further improvements of the photographic characteristics of the film.

Following contact with the treating fluid an equilibration period is required before the film is ready for imagingexposure. Solvent that has been absorbed during treatment is released during this period.

The process of this invention is carried out simply by contacting the film with the selected organic solvent. This is usually accomplished by immersing the film in a liquid bath containing the solvent or in a zone containing solvent vapor as for example, above a heated liquid bath, and thereafter in a liquid water bath where the two-stage treatment is employed. The particular time and temperature employed during such contact will vary depending upon the nature of the vehicle used in the vesicular film and the type and extent of photodate have been obtained where the acetonitrile or alkanol fluid is maintained at a temperature of about 20-60 C., preferably 20-40 C. for about l-l 00 seconds. These temperatures and times apply to the use of either a liquid bath treatment or treatment by vapor phase acetonitrile or alkanol. Where a vapor phase is generated above a liquid bath by heating the liquid bath, the liquid bath will generally be at a temperature higher than that desired in the vapor phase. Moreover, a vapor temperature gradient has been observed in such a situation with the vapor temperature decreasing as distance from the liquid bath surface was increased. Accordingly, in such a situation the film to be treated is passed through the appropriate vapor zone above the liquid having the desired temperature.

Where the second stage water treatment is employed,

a temperature range of about 2090 C. for the water with a contact time of about l-lOO seconds will usually be highly effective. As noted above, the present invention has the advantage of producing the desired improvement at ambient temperature. A highly useful result can be obtained using a slightly warmed alkanol treatment in the range of 30-40 C. followed by an ambient water treatment, with both steps being completed within a total contact time of one minute or less.

Following immersion, solvent is released from the film during an equilibration period. Thismay be conveniently accomplished by storing the film so that the vehicle surface is in communication with the ambient atmosphere for a sufficient time to permit substantial release of solvent. lf no solvent is released prior to imagewise exposure, the effects of the treatment are generally not great, or the film may even be substantially photographically inoperative. Genrally, release of as much solvent as possible is desired so as to approach zero solvent retention. Retention of less than about 1% solvent is a practical goal.

The conditions of storage will govern the precise time at which sufficient equilibration has occurred so that the benefits of the treatment are fully obtained. Usually, sufficient solvent release may be obtained with as little asA to /2 hour of equilibration with the ambient atmosphere. In most cases best results are obtained with about 6-48hours of equilibration. Even longer periods may be beneficial in some cases.

The vesicular film formulations which may be subjected to the treatment of this invention are in general conventional and contain the usual elements found in a vesicular film; namely, a synthetic hydrophobic organic polymeric vehicle within which is dispersed a light-sensitive chemical which decomposes to give a gas. The vehicle and light-sensitive element are generally coated on a suitable support such as the polyethylene terephthalate known as Mylar. All vesicular films which have such a structure and composition are contemplated for treatment by the present process. Such vesicular film formulations may optionally contain the usual additives such as a surfactant dispersed through able surfactants are described in copending U.S. Pat.

application Ser. No. 55,976, filed July 17, 1970 now abandoned but refiled as continuation-in-part in US. Pat. application Ser. No. 175,348, filed Aug. 26, 1971, now U.S. Pat. No. 3,779,768 and in copending'U.S. Pat. application Ser. No. 54,011, filed July 10, 1970 now abandoned but refiled as continuation-in-part in U.S. Pat. application Ser. No. 251,826, filed May 9, 1972, now US. Pat. No. 3,779,774.

With respect to the alkanol solvents used in the present treatment, any suitable synthetic organic thermoplastic or thermosetting vehicle for vesicular film may be employed which may be highly linear or cross linked. The only limitation on the choice of vehicle to be treated is that the vehicle should be insoluble in the treating fluid at least under the conditions of thetreatment so as to retain its physical integrity as a useful photographic film. Suitable vehicles that are resistant to lower alkanol solvents and which may be benefited by the present treatment include the diverse synthetic organic polymeric vehicles described in the prior art including the vinyl polymeric vehicles described in the above-referenced US. Pat. No. 3,149,971, as well as the organic polymeric vehicles disclosed in US. Pat. Nos. 3,032,414 and 3,161,511. These preferred synthetic organic polymers used as the vehicle provide a moisture stable image after exposure and development. Such synthetic polymeric vehicles are distinguished from the older, naturally occurring non-synthetic vesicular vehicle materials such as gelatin which do not provide a vesicular image that is as stable under high moisture conditions.

In the present invention two classes of synthetic polymeric vehicles have been shown to respond to the process in a highly effective manner. The first class of such vehicles is formed from a copolymer of a larger amount of a nitrile of the formula:

CHa=O G N copolymerized with a minor amount of a hydroxy substituted acrylate of the formula:

in which X and Y are individually selected from hydrogen, methyl, and chlorine and Z is the alkylene-oxy in which n is an integer from 24, m is an integer from l2 provided thatwhen m is 2, n is 2, and further provided that a hydroxyl group is substituted for a hydrogen atom of Z.

Vehicles of this type are disclosed and claimed in copending US. Pat. application Ser. No. 72,913, filed Sept. 17, 1970. As disclosed in-said application, outstanding results are obtained where the copolymer is formed from 80-96 weight percent of methacr'ylonitrile Function 7 polymer of an epihalohydrin and a dihydric phenol. Such vehicles are disclosed in copending US. Pat. application Ser. No. 866,753, filed Oct. 15, 1969, now US. Pat. No. 3,622,333, with a preferred species thereof being a polymer of epichlorohydrin and 2,2- bis(p-hydroxy phenyl) propane. Specific examples of other types of vehicles which may be used in the present invention will be described in the working examples v which follow.

The alkanol which is preferably used in the present process is methyl alcohol although the other alkanols having up to about 3 carbon atoms including ethyl alcohol, propyl alcohol, and isopropyl alcohol are also shown to be highly effective. Higher molecular weight alcohols such as butyl alcohol are generally less desirable and may require impractieally longer treatment times and/or higher temperatures. As mentioned earlier, where the vesicular film vehicle is a linear poly (hydroxy ether) of the type disclosed in the above referenced US. Pat. application Ser. No. 866,753, acetonitrile can be used to improve the photographic characteristics of the film in a comparable manner. Acetonitrile appears to be unique in combination with the poly (hydroxy ether) vehicle. Numerous attempts to employ solvents other than alcohols with this and other vehicles were unsuccessful in the present context.

Example 1 illustrates the typical preparation and treatment of a vesicular film in accordance with this invention and the manner for testing its photographic properties. The experimental work reported in the other examples generally followed the same procedure except where indicated otherwise.

EXAMPLE I Vesicular films were prepared from the following formula:

Component Parts by Weight Vehicle Eponol 55 S Sensitizer Andrews Diazo No. 9 (1.3 Surfactant L-79 0.04 Surfactant L-5202 0.005 Solvent Methyl ethyl ketone 8 (MEK) Solvent Z-Methoxy ethanol 16 Eponol 55 is a poly (hydroxy ether) made by Shell Chemical Company from epichlorohydrin and 2,2- bis(4-hydroxyphenyl) propane, Bisphenol A. Andrews Diazo No. 9 is Andrews Paper and Chemical Companys p-diazo-N,N-diethylaniline zinc chloride. L-79 and L-5 202 are Union Carbide s silicone surfactants. These are among the optional additives for vesicular film mentioned previously.

The diazo compound was dissolved in 2- methoxyethanol to a 13 percent solids solution; to this stirring solution was added the L-79 in a 25 percent 6 water and dried with tissue paper. A third film was im- A substantial improvement in photographic characmersed for 10 seconds in ambient (22 C.) methanol teristics was obtained for the methanol treated sample, and afourth film was immersed for seconds in ambinot bl thr shold speed was increased by 3.5 times. ent methanol and dried similarly. Equilibration was accomplished in the ambient atmosphere in about 16 5 EXAMPLE r hours. The treated films were then given identical ex- Vesicular films were, prepared from the following forposures of 60 seconds through a Kodak Photographic mula: Step Wedge No. 3, 4 inches away from a 325 watt Hanovia Mercury vapor lamp 654A10 and then devel- Funcfim Parts by weigh oped at 110 C. in a Canon Kalfile Developer 360VS. 10 vehicle Metihgcryionim164mm 2 A fifth film, wh1ch was not treated, was also exposed S g g g p y g O08 ensltlzer n rews 12120 0. and developed 1n l1ke fashlon. PIOJCCUOI'I dens ty (f Surfactant Disperse Ayd i 0.02 4.5)was measured onaMacBeth Quantalog Densltome Soivent A AEK l D f:

' So vent imethy formamide( MF) eter Model TD205. Photographic characterlstlcs of solvent Tetrahydrofumn (THF) 04 t e e t me ws esstql qw a 3 3 3 15 3 3.

Visbl Speed at Treatment Steps Dmax Dmin OD=l Dmin+0.l

amma

None 2 0.98 0.08 60 seconds 22C. Water 2 1.71 0.07 4.74 0.19 0.39 15 seconds 85C. Water 7 1.72 0.06 3.33 0.60 0.91 10 seconds 22C. methanol 7 1.74 0.08 3.48 0.60 0.87

l5 seconds 22C. methanol 8 1.75 0.08 2.96 0.63 0.97

Ambient water did not significantly improve photo- The vehicle was prepared by emulsion copolymergraphic characteristics over those for the untreated ization of methacrylonitrile and methacrylic acid in a film. The ambient methanol treated samples showed 90/10 weight ratio. Disperse-Ayd No. 6 is a surfactant greatly improved characteristics. These improved charfrom Daniel Products Company. The diazo compound acteristics were matched only when the film was subwas dissolved in the DMF and to this stirring solution jected to water at a substantially elevated temperature. was added a solution of the Disperse-Ayd No. 6 in the U THF. The combined solution was then added to the EXAMPLE stirring solution of the vehicle in MEK. Film prepara- Vesicular films were prepared from the following fortion w as esc b d in EXamPle A vesicular film mula: H thus obtained was immersed for 60 seconds in ambient Function Component Parts by Weight (23 C.) water and dried with tissue paper.- Another film was immersed for 60 seconds in ambient (23 C.)

Veh'de Methacrybnmle methanol and dried in like fashion. Equilibration was homopolymer l Sensitizer Andrews ia Nil 9 1 40 accomplished 1n the amb1ent atmosphere 1n about 1 /2 2 i 'i g h l 2 hours. The films were then exposed and developed as 0mm oxyet am) described in Examplel, the follow i r1 g re sults:

V Visbl Speed at Treatment Steps Dmax Dmin OD=l Dmin+0.l

amma

60 seconds 23" C. Water 6 1.54 0.08 3.68 0.l8 0.52 60 seconds 23C. methanol 8 1.67 0.08 3.81 0.47 0.74

The vehicle was prepared by emulsion polymeriza- Photographic characteristics for the methanol tion of methacrylonitrile. A vesicular coating mixture treated sample were improved over those for the water and films were prepared in generally the same manner treated film, viz, maximum density was increased,

as described in Example I. The film thus obtained was speed at optical density of l was 2 times faster, and immersed for 60 seconds in 30 C. water and dried withh h ld Speed was increased b 1 7 timestissue paper. Another film was immersed for seconds in 30 C. methanol and dried likewise. Equilibration was accomplished inthe ambient atmosphere in' EXAMPLE IV about one-half hour. These films were then exposed, developed, and measured as described in Example I 60 Vesicular films were prepared from the following forwith the following results: mula:

Visbl Speed at Treatment Steps Dmax Dmin OD=l Dmin+0.l

amma

60 seconds 30 C. water 3 0.75 0.07 2.67 0.25 60 seconds creased by a factor of 2.6.

Thevehicle prepared by emulsion copolymerization of methacrylonitrile and 2-hydroxyethyl methacrylate in a 75/25 weight ratio. L-540 is a Union Car- ..Pld l ql lfi r The srasseawaives $.51

The vehicle was prepared by emulsion copolymerization of methacrylonitrile and 2-hydroxyethyl methacrylate in a 90/10 weight ratio. The formula was pre-. pared essentially as described in Example [V and films prepared as described in Example I. The vesicular film thus obtained was immersed for 30 seconds in ambient (23 C.) water and dried with tissue paper. Another film was immersed for 30 seconds in ambient (23 C.) methanol and dried as above. Equilibration was accomplished in the ambient atmosphere in about /2 hour. The two films were then exposed and developed as described in Example I with the following results:

Visbl Speed at Treatment Steps Dmax Dmin 0D=l Dmin+,0.l

amma

30 seconds 23 C. water 6 0.l3 0.07 30 seconds 23 C. methanol 9 1.37 0.06 1.71 0.30 0.96

solved in 0.7 parts of Z-methoxyethanol; to this stirring solution was added the L-540 as a 25 percent solution in 2-methoxyethanol. This mixture was then added to a stirring solution of the copolymer in the remaining solvents. Vesicular films were prepared as described in Example l.

A film thus obtained was immersed for 60 seconds in stantially reduced, speed at OD of l was increased by a factor of 1.5, and speed at the threshold level was in- EXAMPLE V :7 Vesicular films were prepared from the following form i The vesicular film was essentially unaffected by the water treatment, whereas the methanol treatment produced good photographic characteristics.

EXAMPLE Vl Vesicular films were prepared from the following forla Component Parts by Weight I ambient (23 C.) water and dried with tissue paper. An- Function a other film was immersed in ambient (23 C.) methanol Vehicle Melhacrylonimlbz 25 and dried with tissue paper. Equilibration was accomhydroxy-ethyl t methacrylate copolymer pl shed in the ambient atmosphere in about hour. SenSm-zer Andrews maze 9 0J0 v The films were exposed and developed as described in s v t cetonitrne l0 Example I with the following results: solver zMehmyethaml Visbl Speed at Treatment Steps Dmax Dmin 0D=l Dmin+0.l

- amma 60 seconds 23C. water 9 L60 0.06 8.58 0.20 0.90 60 seconds 23C. methanol I3 L 0.18 1.13 0.33 1.32

Gamma for the methanol treated sample was sub- The vehicle was the same as described in Example V.

Theformula was prepared essentially as described in Example IV and films prepared therefrom as described in Example I. A vesicular film thus obtained was immersed for 60 seconds in 40 C. water and dried with tissue paper. Another film was immersed for seconds in 40 C. methanol and dried as above. Equilibration was accomplished in the ambient atmosphere in about hour. The thus treated films were then exposed and developed as described in Example I, with the following results:

Visbl Speed at Treatment Steps Dmax Dmin 0D=l Dmin+0.l

amma

60 seconds 40 C. water 8 1.6] 0.05 2.6l 0.45 0.81

60 seconds 7 40 C. methanol 14 1.63 0.08 2.37 0.68 1.12

' 2-Methoxycthan0l Photographic characteristics for the methanol treated film were improved, especially in speed, viz, at OD of 1 speed was increased by a factor of 1.7 and at the threshold level by a factor of 2.

EXAMPLE Vll Vesicular films were prepared from the following for- 'fiiaiali"eom bnh '8 A anttywagm Improvement in photographic characteristics was obr ed fil wat rtreatment Vehicle Formvar 7/955 2.4 f 3: methanol t cat e Sensitizer Andrews Diazo No. 9 0.096 p Surfactant Disperse-Ayd No. 6 0.048

Solvent Ethylene Dichloride l8 I Solvent Z-Methoxyethanol 0.8 EXAMPLE IX Formvar 7/95S is a poly (vinyl formal) inade by Mom miller santo Chemical. The diazo compound was dissolved in the 2-methoxyethanol and to this was added the Dis- 10 perse-Ayd No. 6 as a 10 percent solution in ethylene Function Component I Pans by weight dichloride. This mixture was then added to the stirring. i l 9 4 Sensmzer Andrews Diazo No. 9 ().l6

solutlon of the Formvar 1n the remaining ethylene di- Solvent MEK 21 chloride. Films were prepared as described in Example Solvent 2-Methoxyethanol l I. A vesicular film thus obtained was immersed for 60 5 r r seconds in 30 C. water and dried with tissue paper- Saran F120 is acopolymer of vinylidene chloride and Another film was immersed for 60 seconds in 30 C- acrylonitrile made by Dow Chemical. The formula was methanol and dried as above. Equilibration was accomprepared by adding a solution of the diazo compound plished in the am ient atmospher in a ut V2 hour. in 2-methoxyethanol to the stirring solution of the These films were exposed and developed as described Saran F120 in MEK. Films were prepared as described in Example I with the following results. in Example A vesicular filrn thus obtained was in Visbl Speed at Treatment Steps Dmax Dmin OD=l Dmin+0.l

' amma 60 seconds C. water 6 1.58 0.07 3.20 0.29 0.63 60 seconds 30 C. methanol 8 1.68 0.10 2.06 0.89 1.45

Photographic characteristics for the sample treated 30 mersed for 30 seconds in 40 C. water and dried with methanol were greatly improved Over thOSe fo h tissue paper. Another film was immersed for 3 0 sec sample.treated with water. Maximum density was inonds in 40 C. methanol and dried as above. Equilibracreased and gamma reduced. Speed at OD=l was intion was accomplished in the ambient atmosphere in c eas d y a factor O and at the threshold y a a or about 16 hours. The films were exposed and developed of 8.5. as described in Example I with the following results:

Visbl Speed at Treatment Steps Dmax Dmin OD=1 Dmin+0.l

amma- 30 seconds C. water 2 1.15 0.05 8.58 0.02 0.18 30 seconds 40 C. methanol 6 1.63 0.05 5.00 0.25 0.52

EXAMPLE VIII I The film was essentially unaffected by the water Vesicular films were prepared from a formula as treatment. Greatly improved photographic characterisscribed in Example V", except that L 54O surfactant ties were obtained for the sample treated with methawas substituted for the Disperse-Ayd No. 6. A film thus 7 obtained was immersed for 30 seconds in ambient (23 C.) water and dried with tissue paper. Another film-was immersed for 30 seconds inambient methanol and EXAMPLE X dried. Equilibration was accomplished in the ambient Ethyl alcohol is also effective in improving photoatmosphere in about /1 hour. The films were exposed graphic characteristics as shown in this example. Films and developed as described in Example I with the folas described in Example I were immersed for 30 seclowing results: 9 959.4 C1 wate 8 !F 59?.Q-.E .h?99 .fl i lle Visbl Speed; Treatment Steps Dmax Dmin OD=l Dmin+0.l

amma

30 seconds 23" c. water 3 0.91 0.07 3.64 0.33 30 seconds 1 23 c. methanol 7 L67 0.12 6.00 0.30 0.62

scribed in Example I, the following results were obtained:

Vesicular films were prepared from the following for- A Visbl Speed at Treatment Steps Dmax Dmin OD=l Dmin-+0.1

amma

30 seconds 40 C. Water 3 1.72 0.08 23 0.22 0.34 30 seconds 40 C. ethanol 6 1.72 0.08 4.45 0.54 0.78

Gamma was greatly reduced and speed increased In Examples iflfxrll and iii exposureanddevelsubstantially with ethanol treatment; photographic opment conditions were: speed at OD=l was two times faster and at the thresh- 10 l. Resolution:

old level 2.8 times faster than for the water treated film. USAF 8007N target; 1 /2 seconds, 6 inches distance gx r gg 2 gg g Hg p Combining a methanol treatment with a follow-up Kodak Photographic Step Wedge; 60 seconds, 3% water treatment greatly reduces the time required to 5 i h di t (f h t hi ld) i h fl i sensitize a vesicular film as shown in this example. Ve- H lamp, Development Temperature 127 C.

sicular films were prepared from a formula similar to I that described in Example IV, except that the copoly-- EXAMPLE mer was a 9 /6 by weight methacry10nitrile-2 This example further illustrates the effectiveness of hydroxyethyl methacrylate. Films were prepared as dethe preferred two-step alcohol-water treatment on a vescribed in Example I. A vesicular film thus obtained sicular film. In this case the vesicular film was the same was immersed in ambient (23 C.) water for 7 minutes as in Example VlI except that it did not contain any surand dried with tissue paper. Equilibration was accomfactant. Equilibration was accomplished inthe ambient plished in the ambient atmosphere in about 72 hours. atmosphere in about 72 hours and 16 hours, respec- A second film was immersed for 10 seconds in 30C. 25 tively. Treatment conditions and film performance methanol, removed, and immediately immersed for were as follows:

vissi'" s a; ai Treatment Steps Dmax Dmin OD=l Dmin-HM amma 5 seconds C. methanol-l- I 30 seconds 23C. water I 7 1.37 0.07 3.53 0.20 0.54 30 seconds 40C. water 4 1.32 0.05 5.00 0.12 0.35

secondsin'ambient waiemhfi dried with tissue paper. E lib i 7 was..- M-.- Mam.-. qui rat on was accomplished 1n the arnb1ent atmo EXAMPLE Xm sphere in over /2 hour. A thlrd film was immersed for l v 5 seconds in 40 C, m than l, v d, d i di- Th1s example illustrates the effectiveness of an alkaatelyirnrners d f 30 e d i bi t t h no] treatment where the alkanol is isopropanol. The vedried with tissue paper. Equilibration was accom- 40 ie l r film employed was he am as that in Example plished in the ambient atmosphere in over /2 hour. The l. The equilibration time for all samples was about 7 films were exposed for 30 seconds and developed at hours exposure to ambient atmosphere. The perform- C. in the manner described in Example I with the ance of such a film treated with isopropanol under the following results: conditions shown as follows: visa 1 i i Speed at Treatment Steps Dmax Dmin OD=l Dmin+0.l

amma 7 minutes i i 23 C. water 8 1.30 0.09 2.14 0.44 0.89

10 seconds 30 C. methanol plus 30 seconds 23 water 14 1.43 0.11 2.14 0.70 L36 5 seconds 40 C. methanol plus 30 seconds 23 water 14 1.40 0.19 1.36 0.111 1.70

V i I I Speed at Treatment Steps Dmax Dmin OD=l Dmin+l).l amrna 30 seconds 40 C. IPA 4 1.68 0.08 10.0 0.22 0.35 30 seconds 40 C. lPA l5 seconds 23 C. water 3 1.70 0.08 10.0 0.22 0.33 30 seconds 40 C. water 3 1.72 0.08 23.0 0.22 0.34

A substantial reduction in film treatment time is ef- I EXAMPLE XIV fected by the methanol-water method accompanied by This example illustrates the effectiveness of acetonisignificant increases in photographic speed. Speed at trile in treating a vesicular film having a poly (hydroxy.

OD of l is increased by factors of 1.8 and 2.3, and at ether) polymer of the type previously described. In this threshold by factors of 3 and 6.5. 1 example the vehicle was the same as that in Example air was continued for a total of 18 hours. A comparison EXAMPLE XVI This example illustrates the long term effect of the treatment provided by this invention. A vesicular film as described in Example I was treated with methanol in accordance with this invention. Another sample was treated with water. Exposure and development 8 /2 months after treatment (during which time equilibration with the ambient atmosphere occurred) .in accordance with the conditions in Example XV gave the following results:

. Visbl I v v Speed at Treatment Steps Dmax Dmin -OD=l Dmin+0.l

v amma 30 seconds I 23 C. methanol 9 1.66 0.07 3.20 0.52 0.92 30 seconds 7 85 C. water 8' L61 0.08 3.33 0.96

was made with the same film which received only a water treatment under the conditions stated. The per formance of the treated film is as follows.

Resl

Visbl Treatment seconds 23C. acetonitrile 15 seconds 23 C. aceto' nitrile 15 seconds 23 C. water seconds 23 C. acetonitrile 30 seconds 23 C.

acetonitrilc 30 seconds 23 C. water 15 seconds 85 C. water 30 seconds 85 C. water rss 4.35

I02 L70 0.07 4.I2

l/mm Steps Dmax' Dmin Gamma OD k 7 EXAMPLE X VII This example illustrates the effectiveness of the aceton'itrile and alkanols when used in the vapor phase.

Speed at =1 Dmin+ O.l

EXAMPLE xv This examplefurtherillustrates the effectiveness of the present treatment where the vesicular film formulation does not contain a surfactant. In this example the film employed was the same as that in Example I except that no surfactant was added. The film was treated for 15 seconds in ambient, i.e., about 23 C. methanol. The treatment produced a light fog to moderate fog which cleared to a very light fog within /2 hour after treatment. Comparative samples of the same film were also treated for 15 seconds in 85 C. water; no fog developed. Both samples were equilibrated with the ambient atmosphere for 18 hours. Exposure and development conditions were: 60 seconds exposure through a Kodak Photographic Step WedgeNo. 3 and 3% inches distance from the Hanovia Hg arc lamp (distance from heat shield). Development temperature 110" C.

Exposed and developed films were measured on a MacBeth TD205 Densitometer. Characteristic curves gave the following data:

The film sample identified as'Eponol 55 was prepared as in-Exarnple I except that no surfactant was added to the formulation where indicated and the Union Carbide'fluorocarbon surfactant FC-l was substituted for the silicones of Example I in the other instances.

The film sample identified as Sarah F-l20 was prepared as in ExampleIX but no surfactant was used in the formulation.

Treatment was accomplished by placing the film in vapor over a heated 'liquid'bath. Time of exposure and temperatures of the vapor and liquid baths are shown in the table below. The vapor temperature was measured about 7 inches above the liquid and is therefore cooler than the vapor closer to the liquid surface.

The acetonitr'ile vapor treated samples were exposed and developed as in .the preceding examples between 19 and 21% hours after treatment to effect equilibration. The methanol vapor treated samples were e'q'uili brated with the ambient atmosphere between 17 and 18 hours before the same exposure anddevelopment.

Visbl I Speed at Treatment Steps Dmax- Dmin OD=l Dmin-HM 4 amma 15 seconds 7 23 C. methanol 8 1.40 0.08 3.75 0.32 0.76 l5 seconds 7 C. water 4 0.3l 0.08

Results are shown in the following table. Density values are not strictly comparable to the preceding examples. Values are higher due to changes in the densitometers used for the measurements. I

l6 ated with liquid methanol. After eight minutes of equilibration the film was exposedand developed as in the preceding examples. No image was observed. It is estimated from a curve developed from the data in the SENSITOMETRIC PROPERTIES Speed at No. of Visible Dmin Sample Treatment 0.15 Steps Dmax Dmin +0.10 1.00

Acetonitrile Vapor Ep'onol 55/00 NONE 2 2.15 0.13 5.90 0.29 :18

surfactant do. 30 seconds at 41C (liquid at 75C) 6 2.60 0.13 5.35 0.75 0.59 do. '5 seconds at 42C (liquid at 74C) 2.58 0.13 5.70 0.69 i 0.541- Eponol 55/FC-170 NONE 3 2.40 0.14 5.00 0.48 0.34 C10. seconds at C (liquid at 73C) 6 2.62 0.14 5.00 0.30 0.63 do. 5 seconds at 42C (liquid at 74C) 6 2.58 0.14 4,55 0.81 0.64 Methanol Vapor V Eponol lno 30 seconds at 41C (liquid at 51C) 5 2.60 0.13 5.00 0.79 0.61

surfactant do. '15 seconds at C (liquid atC) 6 2.61 0.14 4.60 0.76 0.54 Eponol 55/FC-170 30 seconds at 44C (liquid at 53C) 7 2.62 0.14 3.70 0.97 i 0.79 0. 15 seconds at 60C (liquid at 65C) 7 2.56 0.25 3.65 1.06 0.74 Saran F-lZD/no NONE 3 1.68 0.13 4.00 0.31 0.18

surfactant do. 30 seconds at3SC (liquid at 50C) 6 2.46 0.17 3.65 0.711 0.61 do. 15 seconds at 61C (liquid at 65C) 6 2.46 0.13 3.55 0.79 0.58

EXAMPLE xvni This example illustrates the relationship between 30 time and extent of solvent loss during equilibration and the necessity of an adequate equilibration period so;

that suffieient solvent is released.

The Eponol 55 film of the preceding Example XVII was treated with liquid phase methanol and vapor phase acetonitrile. The following table shows the decrease in solvent retention with equilibration time for the two treatments. I

above table that the film had a retained solvent content of about 5% based on the coating weight.

Similarly the same film was treated with acetonitrile vapor and exposed and developed 1 /2 hours after treatment. Only three steps were observed with no image appearing in the portion of the film receiving the greater vapor treatment. It is estimated from a curve developed from the data in the above table that the film based upon had a 5 percent retained solvent content the coating weight.

SOLVENT WEIGHT Loss MEASUREMENTS Sample wt. Wt. of Equilibr'ation (including retained Time. Hours polyester base), g. Solvent. g.

% Solvent Retention Based on Coating Weight Liquid Methanol Treatment [Actual coating wt. (minus base film) 0.0804 gram] Wfi'ridifiihion has not proceeded for a sufficient period of time and a substantial portion of the solvent is still contained in' the film, the photographic properties of the film may beirnpaired to the point that the. film is useless. As an illustration, the film identified .as Eponol 55 of this and the preceding example was tre- I claim: I 1. 1n the method-for improving the photographic 65 characteristics of vesicular film comprising a synthetic hydrophobic vehicle substantially resistant to physical degradation by lower alkanol solvents coated and dried on a support, said vehicle being of the type adapted to serve as the vehicle for a light-sensitive material to form vesicular images, a light-sensitive material substantially uniformally dispersed in said vehicle; said light-sensitive material being decomposable to form nitrogen gas upon imagewise exposure to actinic radiation, said film being heat developable to form vesicles in the exposed areas, the improvement comprising immersing the film prior to imagewise exposure in a fluid phase alkanol having up to three carbon atoms, and thereafter equilibrating said immersed film prior to said imagewise exposure to permit release of alkanol from the film so that less than about 1 percent is retained therein, the time and temperature of said immersion and the time of said equilibration being sufficient to increase the photosensitivity of the film.

6. A method in accordance with claim I wherein said vesicular film has as its vehicle a film forming thermoplastic linear poly (hydroxy ether) polymer of an epihalohydrin and a dihydric phenol.

7. A method in accordance with claim 1 wherein said 4 vesicular film has as its vehicle a copolymer of about 70-99 weight percent of a nitrile of the formula:

8 cai=t ncn x droxy substituted acrylate of the formula:

in which X and Y are individually selected from hydrogen, methyl, and chlorine.

8. A method in accordance with claim 1 and including' the step of contacting said film with water after said contact with the alkanol.

9. A method in accordance with claim 1 wherein said contact with the alkanol is executed at a temperature of about 20-60 C. for about seconds.

10. A method in accordance with claim 8 wherein said contact with the water is executed at about 2090 C. for about l-lOO seconds.

11. A method in accordance with claim 8 wherein said contact with the alkanol is executed at about 20-40 C., said contact with the water is executed at ambient temperature, and said alkanol is methyl alcohol.

hydroxyethyl methacrylate. 

1. IN THE METHOD FOR IMPROVING THE PHOTOGRAPHIC CHARACTERISTICS OF VESICULAR FILM COMPRISING A SYNTHETIC HYDROPHOBIC VEHICLE SUBSTANTIALLY RESISTANT TO PHYSICAL DEGRADATION BY LOWER ALKANOL SOLVENTS COATED AND DRIDED ON A SUPPORT, SAID VEHICLE BEING OF THE TYPE ADAPTED TO SERVE AS THE VEHICLE FOR A LIGHTSENSITIVE MATERIAL TO FORM VESICULAR IMAGES, A LIGHT-SENSITIVE MATERIAL SUBSTANTIALLY INFORMALLY DISPERSED IN SAID VEHICLE, SAID LIGHT-SENSITIVE MATERIAL BEING DECOMPOSABLE TO FORM NITROGEN GAS UPON IMAGEWISE EXPOSURE TO ACETINIC RADIATION, SAID FILM BEING HEAT DEVELOPABLE TO FORM VESICLES IN THE EXPOSED AREAS, THE IMPROVEMENT COMPRISING IMMERSING THE FILM PRIOR TO IMAGEWISE EXPOSURE IN A FLUID PHASE ALKANOL HAVING UP TO THREE CARBON ATOMS, AND THEREAFTER EQUILIBRATING SAID IMMERSED FILM PRIOR TO SAID IMAGEWISE EXPOSURE TO PERMIT RELEASE OF ALKANOL FROM THE FILM SO THAT LESS THAN ABOUT 1 PERCENT IS RETAINED THEREIN, THE TIME AND TEMPERATURE OF SAID IMMERSION AND THE TIME OF SAID EQUILIBRATION BEING SUFFICIENT TO INCREASE THE PHOTOSENSITIVITY OF THE FILM.
 2. The method in accordance with claim 1 wherein said fluid phase is liquid.
 3. The method in accordance with claim 1 wherein said fluid phase is vapor.
 4. The method in accordance with claim 1 wherein said alkanol is methyl alcohol.
 5. A method in accordance with claim 1 wherein said alkanol is ethyl alcohol.
 6. A method in accordance with claim 1 wherein said vesicular film has as its vehicle a film forming thermoplastic linear poly (hydroxy ether) polymer of an epihalohydrin and a dihydric phenol.
 7. A method in accordance with claim 1 wherein said vesicular film has as its vehicle a copolymer of about 70-99 weight percent of a nitrile of the formula:
 8. A method iN accordance with claim 1 and including the step of contacting said film with water after said contact with the alkanol.
 9. A method in accordance with claim 1 wherein said contact with the alkanol is executed at a temperature of about 20*-60* C. for about 1-100 seconds.
 10. A method in accordance with claim 8 wherein said contact with the water is executed at about 20*-90* C. for about 1-100 seconds.
 11. A method in accordance with claim 8 wherein said contact with the alkanol is executed at about 20*-40* C., said contact with the water is executed at ambient temperature, and said alkanol is methyl alcohol.
 12. A method in accordance with claim 6 wherein said vehicle is a polymer of epichlorohydrin and 2,2''-bis(p-hydroxyphenyl) propane.
 13. A method in accordance with claim 7 wherein said vehicle is a polymer of methacrylonitrile and 2-hydroxyethyl methacrylate. 